Are Antarctic suspension-feeding communities different from those elsewhere in the world?

This paper reviews the trophic ecology of benthic suspension feeders in Antarctic shelf communities, studied within SCAR's EASIZ Programme, in comparison with published information from other seas. Dense benthic suspension-feeder communities capture large quantities of particles and may directly regulate primary, and indirectly, secondary production in littoral food chains. Most work has been performed in temperate and tropical seas; however, little is known about suspension feeders in cold environments. Recent studies on Antarctic littoral benthic suspension feeders suggest the period of winter inactivity may last only a few weeks. This contrasts with the hypothesis that in Antarctic communities there is a prolonged period of minimal activity lasting at least 6 months during the austral winter. Results from other oceans may explain how dense benthic communities could develop under such conditions. Alternative food sources, i.e. the "fine fraction", sediment resuspension, lateral advection and efficient food assimilation may play a significant role in the development of suspension-feeder dominated, very diversified, high biomass and three-dimensionally structured communities on the Antarctic shelf.     

Anti-proliferative effect of two lactic acid bacteria strains of human origin on the growth of a myeloma cell line

AIMS: Twenty lactic acid bacteria strains were isolated from human faeces and tested by MTT assay for stimulation or inhibition of the proliferation of Vero and myeloma cells. METHODS AND RESULTS: None of the strains significantly affected the proliferation of Vero cells. However, two isolates (HN1 and HA8) showed a strong inhibition of myeloma cell proliferation (16.7 and 5.0%, respectively) by MTT assay. CONCLUSION: Both strains have an anti-proliferative effect on a tumoral cell line. SIGNIFICANCE AND IMPACT OF THE STUDY: The beneficial effect of LAB cancer therapy has been linked to their ability for immunomodulation.     

Aligning extracted LC-MS peak lists via density maximization

Rapid improvements in mass spectrometry sensitivity and mass accuracy combined with improved liquid chromatography separation technologies allow acquisition of high throughput metabolomics data, providing an excellent opportunity to understand biological processes. While spectral deconvolution software can identify discrete masses and their associated isotopes and adducts, the utility of metabolomic approaches for many statistical analyses such as identifying differentially abundant ions depends heavily on data quality and robustness, especially, the accuracy of aligning features across multiple biological replicates. We have developed a novel algorithm for feature alignment using density maximization. Instead of a greedy iterative, hence local, merging strategy, which has been widely used in the literature and in commercial applications, we apply a global merging strategy to improve alignment quality. Using both simulated and real data, we demonstrate that our new algorithm provides high map (e.g. chromatogram) coverage, which is critically important for non-targeted comparative metabolite profiling of highly replicated biological datasets.     

Protein engineering towards natural product synthesis and diversification

A dazzling array of enzymes is used by nature in making structurally complex natural products. These enzymes constitute a molecular toolbox that may be used in the construction and fine-tuning of pharmaceutically active molecules. Aided by technological advancements in protein engineering, it is now possible to tailor the activities and specificities of these enzymes as biocatalysts in the production of both natural products and their unnatural derivatives. These efforts are crucial in drug discovery and development, where there is a continuous quest for more potent agents. Both rational and random evolution techniques have been utilized in engineering these enzymes. This review will highlight some examples from several large families of natural products.     

The structure of Mediterranean rocky reef ecosystems across environmental and human gradients, and conservation implications

Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m(-2)). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.     

Determination of normal human intrathyroidal iodine in Caracas population

This study focuses on the determination of iodine content in healthy thyroid samples on male population from Caracas, Venezuela. Contribution to establish a baseline of iodine content in thyroid glands and hence to compare the iodine thyroid concentration of the Venezuelan population with other countries is also our objective. Male post-mortem individual samples were analyzed using a spectrophotometric flow injection method, based on the Sandell–Kolthoff reaction. The median intrathyroidal iodine concentration was 1443±677 μg/g (wet weight), ranging from 419 to 3430 μg/g, which corresponds to a median of total iodine content of 15±8 mg (ranging from 4 to 37). These results were higher than those values reported in the literature. No correlation of iodine content with age or weight of the healthy gland was found.     

Larval fish communities in the Medes Islands Marine Reserve (North-west Mediterranean)

This study describes the spatio-temporal distribution patternsof fish larvae in a nearshore temperate area off the north-westMediterranean, located in the vicinity of the Medes IslandsMarine Reserve. Our findings suggest that both the abundanceand species richness of the larvae of shorefish species (i.e.resident species) is high in the Medes Islands but also in theadjacent unprotected coastal area. In addition to the largeinshore species component observed in the Medes Islands theresults were also indicative of a significant influx of shelfand oceanic species, and hence it can be concluded that theeffect of protection is not the only factor responsible forthe spatial patterns observed. The larvae of certain shorefishspecies, e.g. Coris julis, Boops boops, Serranus hepatus, Blenniidaeand Gobiidae undergo significant dispersal out towards the opensea, while other species, e.g. Tripterygion tripteronotus andGobiesocidae were able to maintain distributions that remainin the vicinity of the adults, confirming that pelagic larvaeare not necessarily at the mercy of passive dispersal.     

Endogenous,Tissue-Specific Short Interfering RNAs Silence the Chalcone Synthase Gene Family in Glycine max Seed Coats

Two dominant alleles of the I locus in Glycine max silence nine chalcone synthase (CHS) genes to inhibit function of the flavonoid pathway in the seed coat. We describe here the intricacies of this naturally occurring silencing mechanism based on results from small RNA gel blots and high-throughput sequencing of small RNA populations. The two dominant alleles of the I locus encompass a 27-kb region containing two perfectly repeated and inverted clusters of three chalcone synthase genes (CHS1, CHS3, and CHS4). This structure silences the expression of all CHS genes, including CHS7 and CHS8, located on other chromosomes. The CHS short interfering RNAs (siRNAs) sequenced support a mechanism by which RNAs transcribed from the CHS inverted repeat form aberrant double-stranded RNAs that become substrates for dicer-like ribonuclease. The resulting primary siRNAs become guides that target the mRNAs of the nonlinked, highly expressed CHS7 and CHS8 genes, followed by subsequent amplification of CHS7 and CHS8 secondary siRNAs by RNA-dependent RNA polymerase. Most remarkably, this silencing mechanism occurs only in one tissue, the seed coat, as shown by the lack of CHS siRNAs in cotyledons and vegetative tissues. Thus, production of the trigger double-stranded RNA that initiates the process occurs in a specific tissue and represents an example of naturally occurring inhibition of a metabolic pathway by siRNAs in one tissue while allowing expression of the pathway and synthesis of valuable secondary metabolites in all other organs/tissues of the plant.